EEE aerial spray in 14 Michigan counties to begin Monday night

An aerial spray that was set to be delivered this weekend in 14 counties in Michigan was delayed due to rain, but is scheduled to begin around 7:30 p.m. Monday.

The spraying was first set to begin Sunday to fight the eastern equine encephalitis virus, which has killed three people and been recorded across the southern half of the state.

But the Michigan Department of Health and Human Services said Sunday night that the inclement weather had forced a postponement of those plans. The agency is now set to begin spraying in Barien, Cass, St. Joseph and Van Buren counties, weather permitting.

Officials announced Friday that Michigan and local health departments in 14 counties would conduct spraying for the first time since 1980 to combat the virus, which has been confirmed in humans or animals in the southern half of the state.


The pesticide being used is Merus 3.0 which is an organic pesticide containing 5 percent pyrethrin. Pyrethrins are chemicals found naturally in some chrysanthemum flowers. They are a mixture of six chemicals that are toxic to insects. Pyrethrins are commonly used to control mosquitoes, fleas, flies, moths, ants and many other pests. Pyrethrins have been registered for use in pesticides since the 1950s.

In general, health risks are not expected during or after spraying. No special precautions are recommended; however, residents and individuals who have known sensitivities to pyrethrins can reduce the potential for exposure by staying indoors during spraying. 

Aerial spraying is not expected to have any impacts on surface water or drinking water.

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Aerial spraying will be conducted in the nighttime hours as this is when mosquitos are more active. It is also when fish are less likely to be at the surface feeding and honeybees are most likely to be in their hives. However, owners should cover small ornamental fishponds during the night of spraying. While it is not necessary to bring animals indoors during spraying, concerned pet owners can bring animals inside during spraying.


EEE has a 33 percent fatality rate for those who become sick from the disease. For kids under 15 years old and adults over the age of 50, the fatality rate can rise as high as 50 percent.

Symptoms exhibited by the disease aren't very obvious. Of the 4 to 5 percent of people who do contract the disease and show symptoms, they include chills, fever, weakness, muscle and joint pain and can last up to two weeks. However, for the 1 percent of people who do show serious symptoms, they include neurologic issues like inflammation of the brain.

EEE is typically a serious problem for horses, which is why a vaccine was developed if they contract the disease. No vaccine exists for humans.

People are urged to guard against mosquito bites. The department is encouraging officials in affected counties to consider postponing, rescheduling or canceling outdoor activities including sports occurring at or after dusk until there's a hard frost. 

The projection of warm weather is one of the factors that led MDHHS to make the decision to spray. 

Fox 2 reported on this story from Southfield, Mich. 

The Associated Press contributed to this report